expression.java

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/* Copyright (c) 1995-2000, The Hypersonic SQL Group.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the Hypersonic SQL Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE HYPERSONIC SQL GROUP,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals 
 * on behalf of the Hypersonic SQL Group.
 *
 *
 * For work added by the HSQL Development Group:
 *
 * Copyright (c) 2001-2005, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


package org.hsqldb;

import org.hsqldb.HsqlNameManager.HsqlName;
import org.hsqldb.index.RowIterator;
import org.hsqldb.lib.HashSet;
import org.hsqldb.lib.HsqlArrayList;
import org.hsqldb.store.ValuePool;

// fredt@users 20020215 - patch 1.7.0 by fredt
// to preserve column size etc. when SELECT INTO TABLE is used
// tony_lai@users 20021020 - patch 1.7.2 - improved aggregates and HAVING
// fredt@users 20021112 - patch 1.7.2 by Nitin Chauhan - use of switch
// rewrite of the majority of multiple if(){}else{} chains with switch(){}
// vorburger@users 20021229 - patch 1.7.2 - null handling
// boucherb@users 200307?? - patch 1.7.2 - resolve param nodes
// boucherb@users 200307?? - patch 1.7.2 - compress constant expr during resolve
// boucherb@users 200307?? - patch 1.7.2 - eager pmd and rsmd
// boucherb@users 20031005 - patch 1.7.2 - optimised LIKE
// boucherb@users 20031005 - patch 1.7.2 - improved IN value lists
// fredt@users 20031012 - patch 1.7.2 - better OUTER JOIN implementation
// thomasm@users 20041001 - patch 1.7.3 - BOOLEAN undefined handling
// fredt@users 200412xx - patch 1.7.2 - evaluation of time functions
// boucherb@users 20050516 - patch 1.8.0 - remove DITypeInfo usage for faster
//                                         statement compilation

/**
 * Expression class.
 *
 * The core functionality of this class was inherited from HypersonicSQL and
 * extensively rewritten and extended in successive versions of HSQLDB.
 *
 * @author Thomas Mueller (Hypersonic SQL Group)
 * @version    1.8.0
 * @since Hypersonic SQL
 */

/** @todo - fredt - constant TRUE and FALSE type expressions have valueData of
  * type BOOLEAN, while computed expressions have no valueData; this should be
  * normalised in future
  */
public class Expression {

    // leaf types
    static final int VALUE     = 1,
                     COLUMN    = 2,
                     QUERY     = 3,
                     TRUE      = 4,
                     FALSE     = -4,    // arbitrary
                     VALUELIST = 5,
                     ASTERISK  = 6,
                     FUNCTION  = 7,
                     LIMIT     = 8,
                     ROW       = 9;

// boucherb@users 20020410 - parametric compiled statements
    // new leaf type
    static final int PARAM = 9;

// --
    // operations
    static final int NEGATE   = 10,
                     ADD      = 11,
                     SUBTRACT = 12,
                     MULTIPLY = 13,
                     DIVIDE   = 14,
                     CONCAT   = 15;

    // logical operations
    static final int NOT           = 20,
                     EQUAL         = 21,
                     BIGGER_EQUAL  = 22,
                     BIGGER        = 23,
                     SMALLER       = 24,
                     SMALLER_EQUAL = 25,
                     NOT_EQUAL     = 26,
                     LIKE          = 27,
                     AND           = 28,
                     OR            = 29,
                     IN            = 30,
                     EXISTS        = 31,
                     ALL           = 32,
                     ANY           = 33,
                     IS_NULL       = 34;

    // aggregate functions
    static final int COUNT       = 40,
                     SUM         = 41,
                     MIN         = 42,
                     MAX         = 43,
                     AVG         = 44,
                     EVERY       = 45,
                     SOME        = 46,
                     STDDEV_POP  = 47,
                     STDDEV_SAMP = 48,
                     VAR_POP     = 49,
                     VAR_SAMP    = 50;

    // system functions
    static final int IFNULL      = 60,
                     CONVERT     = 61,
                     CASEWHEN    = 62,
                     EXTRACT     = 63,
                     POSITION    = 64,
                     TRIM        = 65,
                     SUBSTRING   = 66,
                     NULLIF      = 67,
                     CASE        = 68,
                     COALESCE    = 69,
                     ALTERNATIVE = 70,
                     SEQUENCE    = 71;

    // temporary used during parsing
    static final int PLUS     = 100,
                     OPEN     = 101,
                     CLOSE    = 102,
                     SELECT   = 103,
                     COMMA    = 104,
                     BETWEEN  = 106,
                     CAST     = 107,
                     END      = 108,
                     IS       = 109,
                     WHEN     = 110,
                     THEN     = 111,
                     ELSE     = 112,
                     ENDWHEN  = 113,
                     DISTINCT = 114,
                     VIEW     = 115;

    // used inside brackets for system functions
    static final int     AS                      = 122,
                         FOR                     = 123,
                         FROM                    = 124,
                         BOTH                    = 125,
                         LEADING                 = 126,
                         TRAILING                = 127,
                         YEAR                    = 128,
                         MONTH                   = 129,
                         DAY                     = 130,
                         HOUR                    = 131,
                         MINUTE                  = 132,
                         SECOND                  = 133,
                         TIMEZONE_HOUR           = 134,
                         T_TIMEZONE_MINUTE       = 135,
                         DOW                     = 136;
    static final HashSet SQL_EXTRACT_FIELD_NAMES = new HashSet();
    static final HashSet SQL_TRIM_SPECIFICATION  = new HashSet();

    static {
        SQL_EXTRACT_FIELD_NAMES.addAll(new Object[] {
            Token.T_YEAR, Token.T_MONTH, Token.T_DAY, Token.T_HOUR,
            Token.T_MINUTE, Token.T_SECOND, Token.T_TIMEZONE_HOUR,
            Token.T_TIMEZONE_MINUTE, Token.T_DOW
        });
        SQL_TRIM_SPECIFICATION.addAll(new Object[] {
            Token.T_LEADING, Token.T_TRAILING, Token.T_BOTH
        });
    }

    private static final int AGGREGATE_SELF     = -1;
    private static final int AGGREGATE_NONE     = 0;
    private static final int AGGREGATE_LEFT     = 1;
    private static final int AGGREGATE_RIGHT    = 2;
    private static final int AGGREGATE_BOTH     = 3;
    private static final int AGGREGATE_FUNCTION = 4;

    // type
    int         exprType;
    private int aggregateSpec = AGGREGATE_NONE;

    // nodes
    Expression eArg, eArg2;

    // VALUE
    Object      valueData;
    private int dataType;

    // VALUE LIST NEW
    HashSet         hList;
    Expression[]    valueList;
    private boolean isFixedConstantValueList;

    // QUERY - in single value selects, IN or EXISTS predicates
    SubQuery subQuery;
    boolean  isQueryCorrelated;

    // FUNCTION
    Function function;

    // LIKE
    private Like likeObject;

    // COLUMN
    private String      catalog;
    private String      schema;
    private String      tableName;
    private String      columnName;
    private TableFilter tableFilter;                // null if not yet resolved
    TableFilter         outerFilter;                // defined if this is part of an OUTER JOIN condition tree

    // COLUMN
    private int     columnIndex;
    private boolean columnQuoted;
    private int     precision;
    private int     scale;
    private String  columnAlias;                    // if it is a column of a select column list
    private boolean aliasQuoted;

    //
    private boolean isDescending;                   // if it is a column in a order by
    int             joinedTableColumnIndex = -1;    // >= 0 when it is used for order by
    boolean         isDistinctAggregate;

    // PARAM
    private boolean isParam;

    // does Expression stem from a JOIN <table> ON <expression>
    boolean isInJoin;

    //
    static final Integer INTEGER_0 = ValuePool.getInt(0);
    static final Integer INTEGER_1 = ValuePool.getInt(1);

    /**
     * Creates a new boolean expression
     * @param b boolean constant
     */
    Expression(boolean b) {
        exprType = b ? TRUE
                     : FALSE;
    }

    /**
     * Creates a new FUNCTION expression
     * @param f function
     */
    Expression(Function f) {

        exprType = FUNCTION;
        function = f;

        if (f.hasAggregate) {
            aggregateSpec = AGGREGATE_FUNCTION;
        }
    }

    /**
     * Creates a new SEQUENCE expression
     * @param sequence number sequence
     */
    Expression(NumberSequence sequence) {

        exprType  = SEQUENCE;
        valueData = sequence;
        dataType  = sequence.getType();
    }

    /**
     * Copy Constructor. Used by TableFilter to move a condition to a filter.
     * @param e source expression
     */
    Expression(Expression e) {

        exprType = e.exprType;
        dataType = e.dataType;
        eArg     = e.eArg;
        eArg2    = e.eArg2;
        isInJoin = e.isInJoin;

        //
        likeObject = e.likeObject;
        subQuery   = e.subQuery;
        function   = e.function;

        checkAggregate();
    }

    /**
     * Creates a new QUERY expression
     * @param sq subquery
     */
    Expression(SubQuery sq) {
        exprType = QUERY;
        subQuery = sq;
    }

    /**
     * Creates a new VALUELIST expression
     * @param valueList array of Expression
     */
    Expression(Expression[] valueList) {
        exprType       = VALUELIST;
        this.valueList = valueList;
    }

    /**
     * Creates a new binary (or unary) operation expression
     *
     * @param type operator type
     * @param e operand 1
     * @param e2 operand 2
     */
    Expression(int type, Expression e, Expression e2) {

        exprType = type;
        eArg     = e;
        eArg2    = e2;

        checkAggregate();
    }

    /**
     * creates a CONVERT expression
     */
    Expression(Expression e, int dataType, int precision, int scale) {

        this.exprType    = CONVERT;
        this.eArg        = e;
        this.dataType    = dataType;
        this.precision   = precision;
        this.scale       = scale;
        this.columnAlias = e.columnAlias;
        this.aliasQuoted = e.aliasQuoted;

        checkAggregate();
    }

    /**
     * Creates a new LIKE expression
     *
     * @param e operand 1
     * @param e2 operand 2
     * @param escape escape character
     */
    Expression(Expression e, Expression e2, Character escape,
               boolean hasCollation) {

        exprType   = LIKE;
        eArg       = e;
        eArg2      = e2;
        likeObject = new Like(escape, hasCollation);

        checkAggregate();
    }

    /**
     * Creates a new ASTERISK or COLUMN expression
     * @param table table
     * @param column column
     */
    Expression(String schema, String table, String column) {

        this.schema = schema;
        tableName   = table;

        if (column == null) {
            exprType = ASTERISK;
        } else {
            exprType   = COLUMN;
            columnName = column;
        }
    }

    /**
     * Creates a new ASTERIX or possibly quoted COLUMN expression
     * @param table table
     * @param column column name
     * @param isquoted boolean
     */
    Expression(String table, String column, boolean isquoted) {

        tableName = table;

        if (column == null) {
            exprType = ASTERISK;
        } else {
            exprType     = COLUMN;
            columnName   = column;
            columnQuoted = isquoted;
        }
    }

    Expression(TableFilter filter, Column column) {

        schema    = filter.filterTable.tableName.schema.name;
        tableName = filter.getName();

        if (column == null) {
            exprType = ASTERISK;
        } else {
            exprType     = COLUMN;
            columnName   = column.columnName.name;
            columnQuoted = column.columnName.isNameQuoted;
            dataType     = column.getType();
        }
    }